Means for preventing the unauthorized operation of industrial trucks and the like



Nov. 27, 1945. c. E. COCHRAN 2,389,755

MEANS FOR PREVENTING THE UNAUTHORIZED OPERATION OF INDUSTRIAL TRUCKS AND THE LIKE I Filed June 11, 1943 2 Sheets-Sheet 1 FIG.@

' INVENTOR.

CLYDE E 'OCHRAN 5 M 5 ATTORNEYS Nov. 27, 1945. 2,389,765

. C. E. COCHRAN MEANS FOR PREVENTING THE UNAUTHORIZED OPERATION OF INDUSTRIAL TRUCKS AND THE LIKE Filed June 11, 1943 2 Sheets-Sheet 2 C I INVENTOR.

LYDE E. COCHRAN Z7 ATTORNEYS Patented Nov. 27, 1945 UNITED STATES PATENT OFFICE Clyde E'. Cochran, Cleveland, Ohio, assignor' to The Elwell-Parker Electric Company Application. June 11, 1943', Serial No. 490,426

1 Claim.

This invention relates, as indicated, to means for preventing the unauthorized operation of industrial trucks and the like, but has reference more particularly to a locking device for the control handles of such vehicles.

In my Patent. N 0. 2,338,097, grantedJanuary 4, 1944, I have described a controller for industrial trucks, in which a control handle is provided for controlling the movements or contactors for actuating aseries of resistancesv to control the Speed of the power drive, and in which a second control handle is also provided for controlling the movement of contactors for causing the forward or reverse movement of the truck.

In said application, the forward or reverse control handle, is provided at its lower end with surfaces forming a V, which are adapted to be engaged by a corresponding V-shaped member, the lower end of which is attached to. the truck operators foot pedal in such a way that should the operator leave the truck for any reason, a spring forces the V-sha'ped member against the handle surfaces forming the V with sufficient energy toforce the reverse handle to the upright. or neutral position and thereby open the motor circuit.

Since the directional control handle could readily be moved against the action of such spring, it was possible for unauthorized persons to operate the truck by merely getting on the truck, stepping on the pedal and moving the aforesaid control handle in the desired direction.

The present invention, accordingly, has as its primary object theprovision of means for preventing the operation by unauthorized persons of the directional control handle in industrial vehicles of the character described, particularly when the vehicle is left unguarded.

More specifically, the invention has as its object the provision of novel locking means for preventing operation of the directional control handle by persons other than those authorized to operate the truck.

A further object of the invention is the provision of a locking device for the purpose described, which may be easily and quickly locked and unlocked, and which is in close proximity to the directional control handle, so as to be readily accessible to the operator.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same.

In said annexed drawings,

Fig, l is a fragmentary front elevation of one end of acontrol-ler, having incorporated therein the novelfeatures of the invention;

Fig. 2 is an end elevation of the controller shown in Fig. 1;,

Fig. 3 is a cross-sectional view, taken on the line, 3-3 of Fig.1;

Fig. 4: is a view, similar to Fig. 2, partlyinsection, and showing the control handle in locked condition, as Well as the effect of stepping on the pedal of the truck when the handle is locked;

Fig. 5 is a view similar to Fig. 4, but-showing the control handle in unlocked condition, and

Fig. 6 is a view similar to Fig. 5, but showing the movement of the control handle when in unlocked condition, and as permitted by the depression of the truck-pedal.

Referring more particularly to the drawings, it will be seen that a controller, such. as described in my aforesaid application, includes a shaft. I, rotation of which, as by means of a handle 2, controls the movement of contactors for actuating a series of resistances to control the speed of an industrial truck.

One end of the shaft I isjour-nalled in a bearing 3, which is mounted in a control handle 4, which, in turn, isrotatably mounted in abushin (not-shown) secured within a. bushing support 6 attached to the end wall I of the controller housing.

Surrounding the shaft I is a tubular member 8, preferably of square cross-section, but which may be of any section other than round, and which has mounted thereon, so as to be rotatable therewith, a, drum 9 having a series of longitudinally spaced cams formed integrally therewith, which act in a predetermined sequence, to control the forward and reverse movements of the truck. The cam drum 9 is rotatable independently of the shaft I, as described in the aforesaid application. Rotation of the drum 9 is effected by means of the control handle 4, such handle having a square socket which fits over that portion of the tubular member 8 which extends through the arofesaid bushing. The handle 4 hereinafter termed the directional control or forward and reverse handle, is substantially vertical when in neutral or non-operative position, and is moved from thls position in a counterclockwise direction about the axis of the shaft I to control the direction of movement of the truck.

The handle 4 is provided with an annular portion I2, the lower portion of which is provided with lateral projections I3, having lower surfaces I4 which conjointly form a V.

Formed integrally with an extending from the end wall 1 of the controller housing is a cylinder 15 having a smaller cylinder l6 projecting laterally therefrom at a point intermediate its ends,

the wall of the cylinder I5 having an opening I! therein which is in communication with the interior of cylinder I6.

Mounted for reciprocal movement in the cylinder I5 is a cylindrical plunger [8, having an opening IS in the wall thereof, and provided at its upper end with a cross-head 20, having upper surfaces 2| which are inclined to correspond with the inclination of the surfaces l4 of the handle 4. A plunger rod 22 is mounted for sliding movement within the lower portion of the plunger l8.

Mounted within the cylinder 16 is a key-actuated tumbler lock 23 having a bolt 24 which may be projected into and through the opening H.

The lower end of the plunger rod 22 is attached to the foot pedal (not shown) of the truck upon which the controller is mounted, in such a way that should the operator leave the truck for any reason, a spring (not shown) forces the plunger l8 upwardly, and consequently the cross-head 20 upwardly with sufiicient energy to force the handle to the upright or neutral position (if not already in that position) and thereby opening the motor circuit of the truck. This is brought about by the engagement of the surfaces 2! of the cross-head with the surfaces l4 of the handle, as shown in Fig. 4.

Assuming that the operator has stepped oil the truck so that the parts are in the position shown in Fig. 4, if the operator wishes to lock the handle 4 in the neutral position so as to prevent operation of the truck by unauthorized persons, it is only necessary for him to push the bolt or plunger 24 of the lock 23 inwardly so as to cause it to project through the aligned openings I1 and [9, as shown in Fig. 4, which causes the tumblers in the lock to retain the bolt in this position. This, of course, locks the plunger [8 against vertical movement, so that the handle 4 cannot be moved forwardly or rearwardly. Y

Should an unauthorized person step on the pedal of the truck in order to operate the truck, only the plunger rod 22 will be pulled downwardly, as shown in Fig. 4, and such person will be unable to operate the truck, since he cannot move the I handle 4 from its neutral position.

The operator, when he returns to the truck, may, however, operate the truck by inserting a key in the lock 23, so as to retract the bolt 24 from the opening I9, as shown in Fig. 5, after which the truck may be operated in the usual manner, since the handle 4 may then be moved from its neutral position, by stepping upon the pedal of the truck so as to move the plunger rod 22 downwardly, and then moving the handle 4, as shown-in Fig. 6.

.It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claim.

Having thus described my invention, I claim:

In a device of the character described, a controller mechanism housing, a directional controller handle mounted exteriorly of said housing, a hollow plunger carrying a head at one end thereof engageable with a portion of said handle and adapted to shift said handle to and to maintain it in its neutral position when the plunger is urged against said handle portion, a guide member formed on saidhousing for directing said plunger, said plunger having an opening therein disposed within the guide member, a locking bolt supported in said guide member and movable into said opening in said plunger when the plunger is engaged with said handle portion and the handle is in its neutral position for locking said plunger against movement, and actuating means for said plunger including, a rod extending into the end of the plunger opposite said one end and slidable in said plunger, said rod having a shoulder engageable with the end of the plunger whereby said rod is capable of moving the plunger in the direction of said handle only and is movable in the opposite direction without moving said plunger when said locking bolt is in the opening in said plunger.

CLYDE E. COCHRAN. 

